If it's a 111W, it is a compound feed machine (a combination of needle feed and drop feed) with alternating presser feet , which is another way of saying walking foot. The 151 designation must mean it is a special machine made for the government, 'cuz there's no mention of that particular model from Singer. I don't know why it uses the 211W feet, but that's what you'll need to get. It's also odd that the machine would be a "W", 'cuz that means it was manufactured in Germany which makes no sense if it was during WWII. Do you have the serial number?

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